(1) Field of the Invention
The present invention relates to an apparatus for making a music database of musical information which can be processed by a computer and a retrieval apparatus for retrieving a string of note data items from the music database.
(2) Description of the Related Art
Due to developing computers, various types of information can be processed by computers. Document files including texts, documents and the like are typical information which can be processed by such computers. Due to recent increasing of the capacity of storage units, such as optical disk units, hard disk units and floppy disk units, databases of the above information have expanded. A retrieval system capable of easily retrieving information from a large-size database is developing.
In addition, such computers can also process other information such as musical information. In this case, musical performance information is stored with a file format in a storage unit, and the computer plays a music program in accordance with the musical performance information. Since the file format of the musical information is based on MIDI (Musical Instrument Digital Interface) which is an international standard, musical editing software conformable to the MIDI are rapidly gaining popularity, and the amount of musical information having the MIDI format is rapidly increasing. Thus, as to increasing of MIDI format musical information, it is desired that an apparatus capable of easily making a music database and a retrieval apparatus capable of easily retrieving a desired musical information are developed.
There is a case where it is necessary for a user to retrieve a string of musical notes (a phrase) from a music file in which musical information having the MIDI format is stored. To compose music or to arrange music with reference to phrases included in music previously composed by famous composers, the phrases may be retrieved from a music file in which musical information of music composed is stored. In this case, the phrases can be retrieved from the music file as follows. While strings of musical notes are being read out string by string from a music file from which a phrase is to be retrieved, the desired phrase is compared with the strings of musical notes string by string. It is then determined whether or not the phrase is equal to each of the strings of musical notes.
In the above retrieval method, since the phrase must be compared with strings of musical notes read out from the music file string by string, a long retrieving time is required to retrieve the phrase from the large-size music file. In addition, it is possible that it is desired to retrieve a phrase from a music file with reference to an index including strings of musical notes which have previously been selected from the music file as retrieval keys. However, it is difficult to select, with a high probability, strings of musical notes which can be retrieval keys.
That is, there is, conventionally, no retrieval apparatus capable of easily retrieving a phrase from a music file. Thus, it is difficult for a beginner to compose and to arrange music.